A typical marine fuel tank is designed to be versatile and adaptable. The tank should be capable of easy use in a multitude of watercraft and with a multitude of engines. It should be able to maintain its functionality in a broad range of temperature, weather and storage conditions. The tank should also be able to survive the hazards of transport, either as cargo or in operation on a watercraft. To be competitive in the field of marine fuel tanks, manufacturers desire to be able to produce a tank that meets these requirements and more, and do so in a cost effective manner.
Marine fuel tanks carry flammable and environmentally hazardous liquids. For reasons of safety, ecology and economy, it is especially important that these tanks be leak-free. Improvements in methods of tank manufacture have resulted in single body tank shells that are free of seams or connective interfaces where leaks are most likely to occur. But this single body construction has not reduced the potential for leakage at the interface of the tank shell and the components that are attached to its outer surface. Material creep and component separation are frequently responsible for leaks occurring at the interface of the tank shell and its components. The device of the present application improves the seal between the tank and its components, thereby reducing the potential for leakage at the tank shell/component interfaces caused by material creep or other factors.
At its most basic, a marine fuel system is comprised of an engine connected to a fuel tank via a fuel line. Efficient delivery of fuel from the tank to the engine is at least partially dependent on the condition of the fuel line. The fuel line should be leak free, air tight, and free of kinks which impede the flow of fuel. Kinking can also cause breaks in the fuel line. Typically, the fuel line attaches to the tank at the tank's fuel withdrawal assembly, a component which is partially located on the tank's outer surface, and which also extends into the interior of the tank. The potential for kinking increases as the path the fuel line takes from the tank to the engine deviates from perfect linearity. Therefore, the orientation of the fuel withdrawal outlet in relation to the engine partially determines the amount of kinking force to which the fuel line will be subjected. This orientation also determines how much force the fuel line will reciprocally exert on the fuel withdrawal outlet itself, a potential breakage point. Ideally then, the path from the fuel tank to the engine should be linear. Unfortunately, fuel tanks occupy different locations in different watercraft, and sometimes tanks are moved to multiple locations within a single watercraft. Thus there is no fixed fuel withdrawal outlet position which guarantees a linear fuel withdrawal outlet/engine relationship.
Moreover, the fact that part of the fuel withdrawal is located on the outer surface of the tank means that the withdrawal will occasionally be subject to forces which may shear it from the tank. It is desirable that the fuel withdrawal be able to withstand the shearing forces that it will likely experience in normal conditions of transport and operation (dropping, shifting, bumping, falling or dropped objects, etc.).